Polyurethane resins containing brominated polyol ethers

ABSTRACT

WHEREIN N REPRESENTS AN INTEGER FROM 1 TO 4.   (CH2-O-CH2-CH(-BR)-CH2-BR)N   (HO-CH2)(4-N)-(4-(HO-)TETRAHYDROPYRAN-3,3,5,5-TETRAYL)-   A FLAME-RTARDANT POLYURETHANE RESIN IS FORMED FROM A MIXTURE COMPRISING AT LEAST ONE ORGANIC POLYISOCYANATE AND AT LEAST ONE BROMINATED POLYOL ETHER WHICH CAN BE A 2, 3-DIBROMOPROPYL ETHER OF SORBITOL OR A 2,3-DIBROMOPROPYL ETHER HAVING THE GENERAL FORMULA:

March 2, 1971 Original Filed March 12, 1965 S. CARPENTER ET ALPOLYURETHANES RESINS CONTAINING BROMINATED POLYOL ETHERS 2 Sheets-Sheetk HCHO PLUS 1 K W FIG.I. [L AEH 6 REACTOR 2 TL 1 ATMOSPHERIC TEVAPORATOR AEH ALLYL CHLORIDE PLUS CAUSTIC BUOH 5 '7 I/ 6 FILTRATIONPRESSURE EXTRACTION FOR SALT AUTOCLAVE WITH BuOH REMOVAL f j 3 AEH t 6 TBUOH PLUS 4 4 H20 DRY|NG TOPPING BuOH i s f 1 VA UUM BROMINATION FLZSHER330C- I-5mm.HgA

BROMINATED ALLYL ETHERS OF AEH IN SAMMY CAR ENRIQUE R.Wl

FIGZ.

JOSEPH J. CAHI March 2, 1971 S- CARPENTER T AL f POLYURETHANES RESINSCONTAINING BROMINA'IED POLYOL ETHERS ALLYL CHLORIDE I 2 Sheets-Sheet 2PLUS NaOH 7 I F=\BU.OH 5 I l I FILTRATION PRESSURE EXTRACTION FOR SALT IAUTOCLAVE WITH BuOH REMOVAL Th l I 3 SORBITOL BUOH I PLUS 4 I J I H2O I6 I I I I I DISTILLATION TOPPING DFS T IL fiLN f OPERATION F=BUQH a I HI VACUUM BROMINATION FLASHER --9 r 20-30C. l-5 mm. H A

I BROMINATED ALLYL ETVH ER-S OF SORBITOL l NVENTORS: SAMMY CARPENTERENRIQUE R.W|TT JOSEgl-Y-i J.CAH|LL,JR.

MKM

AGEN T United States Patent U.S. Cl. 260-25 Claims ABSTRACT OF THEDISCLOSURE A flame-retardant polyurethane resin is formed from a mixturecomprising at least one organic polyisocyanate and at least onebrominated polyol ether which can be a 2,3-dibromopropyl ether ofsorbitol or a 2,3-dibromopropyl ether having the general formula:

wherein n represents an integer from 1 to 4.

This is a division of US. patent application Ser. No. 439,466 filed Mar.12, 1965 and issued as US. Pat. No. 3,385,900.

This invention relates broadly to halogenated organic compounds and,more particularly, to halogen-containing (specificallybromine-containing) polyol ethers, i.e., ethers of polyols. The scope ofthe invention also includes method and use features.

The invention is especially concerned with a restricted group ofhalogenated, specifically brominated, polyol ethers having a valuableand unique combination of properties that makes them particularly usefulin industrial, agricultural and other applications. This group consistsof sub-classes (A), (B) and (C) hereafter described.

SUB-CLASS (A) The members of this sub-class are represented broadly bythe general formula wherein X represents a halogen (specificallybromine) atom, R (when present) represents a radical selected from thegroup consisting of alkyl (including cycloalkyl), aralkyl, hydroxyalkyl(e.g., CH OH, -C H OH, etc.), aryl and alkaryl radicals, x and y eachrepresent an integer from 1 to 3, inclusive, z represents an integerfrom 0 to 2, inclusive, and x-l-y-l-z equals 4. When 2: is 0, there isno R group attached to the carbon atom in Formula I to which it is shownas being attached. When X represents a bromine atom, then generalFormula I may be rewritten as follows:

(II) (B1'HzCB1HCH2CO -H2C)x-C(CH20H) wherein R, and x, y and 2 have thesame meanings as given above with reference to Formula I.

Illustrative examples of radicals represented by R in Formulas I and II,and which may be the same or different when there are two Rs (i.e., whenz is 2), are alkyl e.g., methyl, ethyl and propyl through decyl (bothnormal and isomeric forms), cyclopentyl, cyclohexyl, cycloheptyl, etc.;aralkyl, e.g., benzyl, phenylethyl, phenyl- "ice propyl,phenylisopropyl, etc.; hydroxyalkyl, e.g., mono-, di-, tri-, etc.,hydroxylated alkyls corresponding to the aforementioned unsubstitutedalkyls; phenyl, biphenylyl or xenyl, naphthyl, etc.; and alkaryl, e.g.,tolyl, xylyl, ethylphenyl, propylphenyl, isopropylphenyl, etc.Preferably the radical or radicals represented by the R or Rsindividually contain not more than about 7 carbon atoms, morespecifically not more than about 4 or 5 carbon atoms, particularly whenthe compounds are to be used in applications involving theflame-resisting characteristics of the compounds or of compositionscontaining the same.

SUB-CLASS (B) The members of this sub-class are represented broadly bythe general formula wherein X represents a halogen (specificallybromine) atom, and n represents a positive integer from 1 to 4-(preferably from 1 to 3), inclusive. When n represents 4, then no CH OHgrouping is attached to the ring nucleus. When X represents a bromineatom, then each X in Formula III is replaced by Br.

Bromine is the preferred halogen represented by X in Formulas I and III,and the other halogens (chlorine, fluorine and iodine) are not the fullequivalent thereof. However, it is not intended to preclude from thescope of the present invention compounds wherein one or more or all ofthe Xs in Formulas I and III represent one or another of the otherhalogens. Compounds wherein at least one of the Xs represents Br and theremaining Xs are a different halogen (i.e., chlorine, fluorine oriodine) may have advantages in certain particular applications, e.g.,insecticidal, fungicidal, pharmaceutical, etc., applications, or as achemical intermediate.

SUB-CLASS (C) The members of this sub-class consist of halogenated,specifically brominated, ethylenically unsaturated ethers, moreparticularly monoethylenically unsaturated aliphatic hydrocarbon ethers,e.g., allyl, methallyl, propenyl, isopropenyl (beta-allyl), l-butenyl,Z-butenyl (crotyl), 3-butenyl, 1,4-dichloro-2-butenyl, pentenyl,hexenyl, butadienyl, etc., ethers, of the saccharides, more particularlythe monoand polysaccharides, especially the monoand disaccharidesincluding such sugars as, for example, sucrose or cane sugar, dextroseor grape sugar, levulose or fruit sugar, lactose or milk sugar,d-mannose, d-galactose and maltose; raffinose which is a trisaccharide;other sugar polyols such as adonitol, xylitol, arabitol, dulcitol,mannitol, sorbitol (d-sorbitol), which latter compound is also known asl,2,3,4,5,6-hexanehexol, etc.; and the hydrogenated formose condensationproducts of formaldehyde. The same remarks made hereinbefore withrespect to the bromine substituents in the compounds of subclasses (A)and (B) as compared with the corresponding other halogen (chlorine,fluorine and iodine) substituents also are applicable to the compoundsof this sub-class.

Uses of the aforementioned halogenated polyol ethers, in addition tothose previously mentioned, include their use as a component (or as areactant in making a component) of polyurethane foams including rigidpolyurethane foams.

Brominated compounds of the kind embraced by subclasses (A), (B) and (C)can be prepared from the corresponding unbrominated polyol ethers asillustrated by the procedures given in some of the examples whichfollow.

Halogens other than bromine may be introduced in various ways. Forexample, the fiuoro derivatives may be prepared via halogen exchangestarting from the corresponding chloro or fiuoro derivatives and silveror lead fluoride (E. H. Rodd, Chemistry of the Carbon Compounds,Elsevier, 1951, vol. 1A, pp. 331, 677). Chlorine may be introduced intothe polyol ethers by direct addition to the double bond, takingreasonable precautions to compensate for its high reactivity by, forexample, using adequate dilution of the reaction mass and low reactiontemperatures (Rodd, ibid., page 677; Groggins, Unit Processes in OrganicSynthesis, McGraw-Hill Publishing Company, 1947, page 169). The iodinederivatives may be prepared directly from the corresponding ethers andiodine (Rodd, ibid., page 677), or by chlorine or bromine exchange withsodium iodide in acetone, i.e., the socalled Finkelstein reaction (Rodd,ibid., page 331; H. Finkelstein, Ber. 43, 1528 (1910)).

Examples of compounds embraced by Formula I are the monoandbis(2,3-dibromopropyl) ethers of trimethylolethane (TME),trimethylolpropane (TMP), trimethylolbutane, trimethylolpentane,trimethylolhexane and higher members of the homologous series oftrimethylolalkanes; the corresponding ethers of (trimethylol)(phenyl)methane, -ethane, -propane, -butane and higher members of thehomologous series of phenyl-substituted alkanes; themono-(2,3-dibromopropyl) ethers of (dimethylol)[bis(phenyl)]methane,-ethane, -propane and higher members of the homologous series of his(phenyl) alkanes; ethers, corresponding to the monoand bis(phenyl)alkanes just mentioned, of the monoand bis(benzyl) methanes, -ethanes,-propanes, -butanes, etc., and of the monoand bis(tolyl)methanes,-ethanes, -propanes, -butanes, etc., the mono-, his andtris(2,3-dibromopropyl) ethers of pentaerythritol (PE); and thecorresponding chloro, fiuoro and iodo derivatives of the said ethers.Other examples and their obvious equivalents [e.g., the various(2,3-dibromopropyl) ethers of dipentaerythritol] will be apparent tothose skilled in the art from the foregoing, illustrative examples, fromFormulas I and II, and from the meanings of x, y and z in said formulas,and from the numerous illustrative examples of radicals represented by R(when present) that previously have been given.

As starting reactants in making useful halogenated polyol ethers arealkylene oxide adducts, more particularly the ethylene oxide andpropylene oxide adducts, of the polyols used in making the halogenatedpolyol ethers set forth in the preceding paragraph. Thus, instead ofusing trimethylolpropane,

CHEOH CHaCH2-C-CH2OH Cl-IzOH as a starting reactant in making thehalogenated derivative, one may use, for example, a compound representedby the general formula (III-A) wherein x, y and 2 each represent anumber having an average value ranging from 1 to about 5, inclusive. Thealkoxylated polyols are converted to ethylenically unsaturated ethers,specifically allyl ethers, and are halogenated (brominated, chlorinated,fluorinated or iodinated) as herein set forth. Such halogenatedderivatives are particularly useful in making flame-retardant, cellular,polyurethane resins, as well as for other purposes.

Examples of compounds embraced by Formula III are the mono, bis, trisand tetrakis(2,3-dibromopropyl) ethers of anhydroenneaheptitol (AEH),and the corresponding chloro, fiuoro and iodo derivatives.

(Ill-13) Examples of halogenated, specifically brominated, allyl ethersof the carbohydrates, more particularly sugar polyols, of sub-class (C)are the mono-, diand higher poly-(2,3-dibromopropyl) ethers of sorbitol,mannitol, xylitol and other polyols mentioned by way of examplehereinbefore under sub-class (C), and the corresponding chloro, fiuoroand iodo derivatives. In general, etherification of up to an average ofn1 out of the n hydroxyls of a polyol can be effected without difiicultyby suitable adjustment of the reactant ratios. The resulting ether isthen halogenated, specifically brominated.

The increasing importance of modifying normally flammable organicmaterials used, for example, in making textile, household, industrialand other articles, and as construction materials in the building field,has resulted in extensive research on flame-resistant compounds andcompositions. Halogen, phosphorus and nitrogen compounds are extensivelyused in formulations to impart flame-resistance to normally flammableorganic compounds or materials. However, difficulties are encountered inintroducing an amount of the pertinent element that will impart thedesired degree of flame-resistance without adversely affecting the otheruseful properties of the modified compound or material.

The present invention is based on the applicants discovery thathalogenated compounds of the kind hereinbefore described undersub-classes (A), (B) and (C), and particularly the brominatedderivatives, have the unique and unobvious combination of propertiesthat has long been sought in many applications wherein flameresistanceis desired without adversely affecting other useful properties of themodified composition, product or article, e.g., in making polyurethaneresins and foams. This appears to be due to the fact that thehalogenated compounds of this invention do not merely comprisehalogenated, specifically brominated, methyl or methylene groups; butthey contain such halogenated groups in a compound which additionallycontains both ether linkages and hydroxyl groups. The hydroxyl groupsare reactive sites whereby the halogen-containing ether groups can beintroduced into other compounds or compositions, e.g., by reaction withan ester-forming compound, such as a monoor polycarboxylic acid, anaromatic or aliphatic monoor polyisocyanate or -isothiocyanate, andother compounds that are reactive with an active hydrogen atom.

The preferred halogenated polyol ethers of this invention, i.e., thebrominated derivatives, are prepared by contacting the polyol ethercorresponding to the desired brominated polyol ether with bromine (or acompound engendering bromine), advantageously while the unbrominatedpolyol ether is dissolved or dispersed in an inert (substantially inert)liquid reaction medium. Illustrative examples of such reaction media arealkanols, e.g., ethanol, n-propanol, isopropanol, n-butanol and isomericforms thereof, n-pentanol and isomeric forms thereof, and higher liquidmembers of the homologous series. Other examples include saturatedaliphatic hydrocarbons, e.g., heptane through dodecane (both normal andisomeric forms); aromatic hydrocarbons, e.g., benzene, toluene, xylene,etc.; the various halogenated aromatic hydrocarbons including, forexample, the various chloroand bromobenzenes and toluenes, etc.; and thevarious halogenated saturated aliphatic hydrocarbons including, forinstance, chloroform, carbon tetrachloride, ethylene bromide, ethylenechloride, ethylene chlorobromide, unsym. and sym. tetrachloroandtetrabromocthanes, 2- bromo-l-chloropropane, l-bromo-Z-chloropropane,propylene chloride, isobutylene bromide, trimethylene chloride,propylidene chloride and bromide, 1,1-dibromo-, 1,2-dibromo-,1,3-dibromoand 2,2-dibromopropanes, 2,2-dichloropropane, pentamethylenedichloride, etc. Still other examples include ethers, e.g., m-dioxane,p-dioxane, mixtures of mand p-dioxancs, pcntamethylene oxide,tetrahydrofurfuryl ethyl ether, dicthylene glycol diethyl ether, and thevarious normal and isomeric dialkyl ethers, e.g., di-n-propyl ether,n-butyl ether, isobutyl ether, ethyl butyl ether, methyl amyl ether,methyl benzyl ether, phenyl butyl ether, and other known ethers whichare liquid at the reaction temperature. Other examples of inert,anhydrous, liquid, reaction media will be apparent to those skilled inthe art from the foregoing illustrative examples.

By inert or substantially completely inert, liquid medium or liquidreaction medium is meant a liquid medium which is so inert ornon-reactive toward the reactants and the reaction product that it willnot adversely affect the course of the reaction or the constitution ofthe reaction product. By liquid medium (or liquid reaction medium) ismeant a medium which is liquid at the temperature and pressure employedin effecting the bromination reaction. In other words, the inert, liquidmedium in which the reaction may be effected may or may not be a liquidat room temperature (20- 30 C.) or at any other temperature below thereaction temperature. Preferably a liquid medium which is volatile(volatilizable) without decomposition is employed.

The reaction between the bromine (or compound engendering bromine) andthe unbrominated polyol ether may be carried out at temperaturesranging, for example, from about C. to ambient temperature, e.g., 20-30C.

The bromine and the polyol ether are employed in the approximateproportions that are stoichiometrically required to produce the desiredbrominated polyol ether; or with either slightly, e.g., from 0.5 to 10mole percent, in excess of the other. Usually, a small molar excess ofbromine is employed.

Where economic considerations are not of primary importance or incertain other particular situations, one may use compounds engenderingbromine instead of bromine itself. For example, one may employbrominecontaining interhalogen (mixed halogen) compounds such as brominemonochloride. Its use would yield mixed chloro-bromo compounds, and hasthe advantage that it permits a wider latitude in the halogen andhydroxyl content of the products. Also, when it is desired to form themonobromide instead of the dibromide, one may use hydrogen bromideinstead of bromine. The addition at the double bond occurs thusly:

Since HBr additions occur mainly by radical mechanisms, certain problemsare encountered in the use of HBr that are not normally present whenbromine is used. Also, HBr does not add at the double bond at the almostinstaneous rate of elementary bromine.

Among examples of other compounds engendering bromine that may beemployed in the bromination step are certain bromine cemplexes, such aspyridinium perbromide, C N N-Br and dioxane dibromide,

Illustrative examples of polyol ethers that may be halogenated,specifically brominated, to produce the compounds of this invention arelisted below either with reference to a generic or a specific formula:

OH I H B01120 C HOHzC CHsOH C1120 CHr-CH CHz wherein R, when present,and x, y and z have the same meanings as hereinbefore given withreference to Formuas I and II.

The compound of Formula X is a monoallyl ether of AEH, and is a speciesof allyl ethers of AEH that may be represented by the general formulawherein n represents a positive integer from 1 to 4, inclusive, and ispreferably 1 or 2.

The compound of Formula XI is a monoallyl ether of sorbitol, which whenbrominated in accordance with this invention, yieldsmono-(2,3-dibromopropyl) ether of sorbitol. The allylation of both CH OHgroupings of sorbitol yields a diallyl ether of sorbitol which, whenbrominated, provides di-(2,3-dibromopropyl) ether of sorbitol.

The brominated compounds of the invention are made by contacting withbromine an allyl ether of the kind described above while the latter ispreferably dissolved (within which term is included dispersed) in aninert liquid reaction medium.

The amount of the bromine employed is at least the stoichiometricalamount required to convert x number of allyl ether groups in the polyolto x number of 2,3-di-bromopropyl ether groups. Thereafter thebrominated compound is isolated from the reaction mass in any suitablemanner, or is purified by any suitable means such as by flashing oif anyinert liquid reaction medium that may have been employed, followed byfiltration and/or a decolorization treatment as desired or as conditionsmay require.

In practicing the present invention it is not necessary that one startwith the pure or substantially pure polyol ethers. Thus one may, ifdesired, prepare crude allyl ethers of such polyols as AEH, TMP and PEstarting with the parent aldehydes and using standard procedures.

As shown in FIG. 1 and FIG. 2 of the accompanying drawings and inExample 5 that follows, which describe the preparation of monoanddiallyl ethers of AEH, the reaction product from the AEH reactor is 1evaporated at one atmosphere pressure in atmospheric evaporator 2 to abase temperature of C., additional water being added (when a high molarexcess of HCHO is used) to remove most of the HCHO. The crude AEHcontaining sodium formate (NaFo) and 3040% water is charged to anautoclave 3 together with the required amount of allyl chloride and analkali solution, specifically a solution of caustic soda.

The crude allyl ethers of AEH (or of other polyols subjected toallylation) are removed from the autoclave and topped by distillation indistillation topping operation 4 at one atmosphere to remove allylchloride, diallyl ether and allyl alcohol as low boilers. Two shake-outextractions 5 using a suitable solvent, e.g., n-butanol, are applied tothe residue to recover most of the products from salt water containingNaFo and NaCl. Distillation at one atmosphere 6 to remove water as itsazeotrope with n-butanol is used to dry the products and to precipitatedissolved salts which are then removed by filtration in 7.

At this stage the allyl ether of the polyol may be isolated, if desired,by means of a vacuum-flashing step to remove the butanol. However,butanol (n-butanol) serves very satisfactorily as an inert diluent andpermits the rapid addition of a calculated amount of bromine (based onthe number of allyl groups present in the polyol) at ambient temperature(30 C.) in 8. Generally the bromine is added in a slight or asubstantial excess as hereinbefore described, and the excess isconsumed, for example, by bubbling an olefinic hydrocarbon, specificallyethylene or propylene, into the reaction mass until the excess has beenconsumed. Complete removal of butanol from the brominated product isattained by vacuum-flashing the brominated polyol ether at, forinstance, 1-5 mm. HgA pressure and a base temperature of, for example,about 114 C. in vacuum flasher 9.

Surprisingly, in spite of the relatively high water content (e.g., aboutto that is present during the above-described allyl chloride reaction,the allyl chloride efliciency is relatively high, e.g., from about 67%to about 83%. This efficiency indicates that beneficial effects arederived from some source; perhaps either from the lowtemperaturereaction conditions (i.e., about 8090 C.) or as a result of a beneficialsalting-out effect exerted by sodium formate, or by a combination ofboth such influencing factors.

The brominated polyol ethers of this invention are quite viscous atambient temperature (20-30 C.) but flow freely at elevated temperatures,e.g., -80 C.

In order that those skilled in the art may better understand how thepresent invention can be carried into effeet, the following examples aregiven by way of illustration and not by way limitation. All parts andpercentages are by weight unless otherwise specified.

EXAMPLE 1 Trimethylolpropane mono-(2,3-dibromopropyl) ether Thepreparation of the above compound, which also may be named as themono-(2,3-dibromopropyl) ether of TMP, by the direct bromination of TMPmonoallyl other is illustrated by the following equation:

TMP monoallyl ether (851.5 g.; 4.88 moles) is mixed with 500 cc. carbontetrachloride in which it is completely soluble, and the solution isplaced in a 3-necked flask fitted with a stirrer, thermometer anddropping funnel. Bromine, 792 g. (10 g. in excess of theoretical), isintroduced through this funnel. Reaction is almost instantaneous andmildly exothermic, requiring cooling of the reactor with ice water.

The reddish reaction product, containing a slight excess of bromine, isleft at room temperatures (2030 C.) for two hours and then washed asfollows: (a) one wash with aqueous sodium metabisulfite solution todestroy excess bromine (upon bleaching, the organic layer is found toconsist of two phases, viz, CCl and TMP monoallyl ether dibromidephases); (b) two sodium carbonate washes; and (c) two sodium sulfatewashes (water alone tends to emulsify the product). If desired, theexcess bromine can be removed by bubbling ethylene or propylene throughthe reaction mass.

The washed organic layer is stripped free of solvent and water, andfiltered through a steam-jacketed Biichner funnel. The yield is 1305 g.which corresponds to of the theoretical. The product has the followingcharacteristics:

Appearance-Clear, viscous liquid Percent Br (calculated: 47.8% )55.5%Percent OH (calculated: 10.2% 8.1% Iodine number0.9

Acid number0.24

Sp. gravity 20/20-1.599

Viscosity, SUS at F.-250.2

Note: The relatively high Br and relatively low OII contents may be dueto the presence of TMP diallyl ether admixed with the TMP monoallylether of starting reactant.

EXAMPLE 2 Pentaerythritol bis(2,3-dibromopropyl) ether Theaforementioned compound, which also may be named as entaerythritoldiallyl ether tetrabromide, is prepared by the addition of astoichiometric amount of liquid bromine (or with, for example, from 1%to 10% in excess of theoretical), to entaerythritol diallyl ether incarbon tetrachloride solvent at 0 to 10 C.

The reaction mixture is washed with a 2% sodium metabisulfite solutionfollowed by a dilute sodium bicarbonate wash and two water washes.(Instead of the sodium metalbisulfite wash, ethylene or propylene may bebubbled through the reaction mass to remove excess bromine.) The productis isolated by flashing off the carbon tetrachloride under vacuum andfiltering the remaining material through diatomaceous earth. An analysisof the product follows:

EXAMPLE 3 Pentaerythritol tris(2,3-dibromopropyl) ether Theaforementioned compound, which also may be named as pentaerythritoltriallyl ether hexabromide, is prepared by the addition of astoichiometric amount (or using a slight excess) of liquid bromine topentaerythritol triallyl ether using CCL, as a solvent. The temperatureof the reaction mixture is maintained at 0 to 10 C. during the reaction,and after the addition of the bromine the reaction mass is washed with500 ml. of 5% sodium metabisulfite solution, and then neutralized withpotassium carbonate solution. After two 1000 ml. water Washes, thesolvent is flashed from the product and the product is isolated byfiltration. A heat lamp is used to warm the product during filtration.This causes the product to darken. In order to lighten the product it istreated with carbon black and diatomaceous earth, followed by a secondfiltration. The product, which is obtained in a yield corresponding to66% of the theoretical, shows the following upon analysis:

Charge B:

6 moles NaOH246 g. (97%) dissolved in 980 g. H2O

Reaction (Charge B added rapidly to Charge A) Found Theoretical o o 3 5Temp. adiabatic rise from 29 C. to 64 C.; Reacted 823E 3 bg ggg 8 for 60mm; then acidified with HAc Hydrogen, wt. percent 3. 5 3. 3 AtmosphericEvaporation; Distilled to base temp. of ggig fifi fiia 1:; 5 100 C.(Each batch should contaln 5 moles AEH and 6 moles N aFo.)

Bromiuated Bromiuated Data MAE-AEH DAJ-AE H Pressure AutoclaveOperation:

Polyol concentrate weight, g 2, 143 2,179 Moles allyl chloride added 5.5 11.0 Moles NaOH (added as 50 wt. 5. 5 11. 0 Temp. range, C r 80-8080-95 Pressure, p s i g -40 -45 Reaction time, hr 2. 5 2. 5 ToppingOperation:

Moles allyl chloride recovered 0.21 0. 47 Moles allyl reacted per moleAEH 0. 9 1. 7 Allyl chloride efficiency, perceut 83 83 ButanolExtraction and Drying Phase, g..

Two shake-outs using 1,000 cc., organic 2, 940 3, 036 BuOH each time at50-60 0., aqueous 1, 715 2, 348 Distilled (1 atm.) to remove BuOH-H Oazeotrope) Filtration, Weight of salt removed, g 31 20 Bromination inBuOH:

Bromine used, g.-at0ms 9. 06 16. 2 Product wt. after vacuum flashing ofBuOH at 1-5 mm.

HgA and 114 0. base temp, 1, 970 2, 600 Overall yield (based on DMK),percent 90 01 EXAMPLE 4 Pentaerythritol mono-(2,3-dibromopropyl) etherFound Theoretical Bromine, Wt. percent 47. 0 47. 6 Carbon, wt. percent29. 2 28. 6 Hydrogen, Wt. percent- 5. 0 4. 8 Acid number 1. 6 Percenthydroxyl 12. 8 15. 2

EXAMPLE 5 This example illustrates the preparation of brominated allylethers, specifically brominated monoallyl ether and brominated diallylether, of AEH and which are herein sometimes identified for purposes ofbrevity as, respectively, DBMAE-AEH and TBDAE-AEH.

A flow sheet showing the various steps in the process, the processingdetails and recorded data are shown in FIG. 1 and FIG. 2 of theaccompanying drawings wherein the meanings of the various symbols notpreviously identified are as follows:

DMK=Dimethyl ketone (acetone) BuOH=n-Butano1 AEH PROCESSING DETAILS Twoseparate AEH batches prepared and processed through atmosphericevaporation using the following amounts: (Reactant mole ratio: 8 to 1 to1.2 HCHO to DMK to NaOI-I) Charge A:

moles HCHO-8000 g. 15 wt. percent 5 moles DMK296 g. (98%) The propertiesof the brominated allyl ethers of AEH of this example are apaque andcontain traces of BuOH. They do not darken at C. in the presence of air.Other properties and analytical data are tabulated below:

Tetra- Dibromo (DB) bromo (TB) MAE-AEH DAE-AEH Ratio of allyl to AEH 1:1211 Color Hydroxyl, wt. percent 3 10. 65 6. 7 Bromine, wt. percent 3 37.5 46. 3 Carbonyl, wt. percent (as HCHO) 0. 02 0. 05 Ash, wt. percent 0.20. 02 Unsaturation, Wt. percent (as allyl) 0.5 0. 5 Viscosity at 210 F.(eentistokes) 4 l65l60 4 127-115 1 Dark Amber. 2 Amber.

3 Hydroxyl values are lower than calculated, indicating that thesecondary hydroxyl group of AEH does not yield completely to analysis;however, calculated values for unsaturation and for wt. percent Brpresent are in good agreement with the analytical values.

4 The viscosity of the bominated products decreases with time at 210 F.indicating that some degradation occurs.

EXAMPLE 6 This example illustrates the preparation of a brominated allylether of sorbitol, specifically the brominated diallyl ether ofsorbitol, and which is herein sometimes identified for purpose ofbrevity as DAE-sorbitol, i.e., bis(dibromopropyl) ether of sorbitol andwhich is probably a mixture of isomers that includes bis(2,3dibromopropyl) ether of sorbitol.

FIG. 3 of the accompanying drawings indicates the r various steps in theprocess; the processing details and tabulated data are given below:

Brominated DA Processing data sorbitol Pressure Autoclave Operation:

Moles sorbitol added 1 5 Moles allyl chloride added 12. 5 Moles NaOH(added as 50 wt. percent) 12. 5 Temp. range, C 80-00 Pressure, p.s.i.g25-40 Reaction time, hr 3 Topping Operation:

Moles allyl chloride recovered O. 8 Moles allyl reacted per molesorbitoL 2 Allyl chloride efficiency, percent 86 Butanol Extraction andDrying Phase, g.:

Two shake-outs using 1,000 cc., organic 2, 913 BuOH each time at 50600., aqueous 2, 037

(Distilled (1 atm.) to remove BuOH-H O azeotrope) Filtration, Weight ofsalts removed, g 51 Bromination, Bromine used, g.-atoms 19. 5 ButanolFlashing:

Evaporated to 0. at 1-5 mm. HgA Ior brominated sample. Weight obtained2, 307 Over-all yield (based on sorbitol) 79 1 910 g. added to 200 cc.hot water.

The properties of tetrabrorno DAE-sorbitol, which is opaque, aretabulated below, together with pertinent analytical data:

Color Dark amber Ratio of allyl to polyol 2:1 Hydroxyl, wt. percent 17.0 Bromine, wt. percent 58.8 Carbonyl, Wt. percent (as HCHO) 0.10 Ash,wt. percent 0.01 Unsaturation, wt. percent (as allyl) 0.20 Acid, wt.percent (M.W. 100) 0.08 Viscosity at 210 F. (centistokes) 123 1 Thehydroxyl value is lower than expected from the calculated valueindicating either incomplete or sluggish reaction of hydroxyl in thecompound by acetic anhydride analysis.

Brominated MAE-sorbitol, more particularly mono- (2,3-dibromopropyl)ether or sorbitol, is prepared as described above with reference to thepreparation of tetrabromo DAE-sorbitol with the exception that 6.25 g.moles each of allyl chloride and of NaOH are used instead of 12.5 g.moles of each of said reactants, and only about 9.75 g. atoms of Br isused instead of 19.5 g.

The halogenated, specifically brominated, polyol ethers of thisinvention are particularly useful in the production of flame-retardantpolyurethane foams, and especially rigid foams.

Foamed polyurethane resins are made by reacting a compound containing aplurality of isocyanate groups, e.g., tolylene diisocyanate, with apolyhydroxy compound. Upon bringing these reactants together, theisocyanate and hydroxyl groups of the compounds containing the sameco-react to provide polyurethane linkages whereby the molecules arecrosslinked and a solid, resinous structure is obtained. In forming suchresins a gas-producing agent is commonly included and, as a result ofits action, the resin (before it solidifies) is converted into afoamlike or cellular state. This cellular structure of the resin ispermanently retained after the mixture has reacted sufficiently to yielda solid body.

An objectionable characteristic of these foamed polyurethane resins,which are useful as heatand soundinsulating materials, as packagingmaterials, as cushioning materials in household, industrial and otherapplications, etc., is their poor flame resistance. Attempts to solvethis problem have usually involved the addition of certain knownfire-retardant substances, e.g., finely divided antimony trioxide. Suchmaterials improve the flame resistance of the foamed resin provided thata sufficient amount thereof (e.g., or more by weight) is used. However,the use of such large amounts of flame-retardant material causesStratification or separation or other problems in the production of thefoam; and, in addition, is highly objectionable because it reduces thestrength of the foam. Furthermore, such flame-retardant substances asantimony oxide yield a foam that has strong after-glow characteristicseven after the ignited foam has been extinguished.

One proposed solution (see US. Pat. No. 3,134,742) to the foregoingproblem is the incorporation into the foamable mixture of a system ofsynergistically co-acting flame-retarding agents. One of these agents isa substance containing a relatively high proportion of nitrogen andphosphorus, e.g., a polyamide of an oxyacid of phosphorus, and the othercomprises a liquid phosphoruscontaining polyol, e.g., a hydroxyalkylester of an oxyacid of pentavalent phosphorus.

One embodiment of the present invention comprises a different solutionto the problem briefly described above with reference to the productionof polyurethane foams having flame-retarding characteristics. Broadly,this embodiment comprises incorporating into a polyurethane resin in anymanner whatsoever, but preferably in the form of a simple or mixed esterthereof, a halogenated,

specifically brominated, polyol ether of the kind with which thisinvention is concerned.

Illustrative examples of organic polyisocyanates that can be used inpracticing this embodiment of the present invention are listed below:

Tolylene-Z,6-diisocyanate Tolylene-2,4-diisocyanate Diphenylmethane-4,4'-diisocyanate m-Phenylene diisocyanate4-isopropyl-1,3-phenylene diisocyanate 4-methoxy-l,3-phenylenediisocyanate 2,4-diisocyanato-diisopropyl-1,3-phenylcne diisocyanate4-chloro-1,3-phenylene diisocyanate 3,3'-dimethyl-4,4'-diisocyanatodiphenyl methane3,3-bitolylene-4,4'-diisocyanate 2,4-diisocyanatodiphenyl ether4,4-methylene-bis(phenylisocyanate) Mesitylene diisocyanateo-Nitrobenzidine diisocyanate Durylene diisocyanate Benzidinediisocyanate Tetramethylene diisocyanate 4,4'-diisocyanato dibenzyl1,5-naphthalene diisocyanate Hexamethylene diisocyanate Liquidpolymethylene polyisocyanate (PAPI) 1,3,5-benzene triisocyanateTolylene-2,4,6-triisocyanate 2,4,4-triisocyanatodiphenyl etherTritolylmethane triisocyanate Other examples include, for instance, thereaction product of tolylene diisocyanate with trimethylolpropane at anNCO/OH ratio of 2:1, and the reaction product of tolylene diisocyanatewith 1,2,6-hexanetrio1 at an NCO/ OH ratio of 2:1.

Instead of using an organic polyisocyanate as the reactant with thepolyhydroxy compound (e.g., a hydroxylterminated polyester and/or ahydroxyl-terminated polyether) to form the polyurethane, there can beused prepolymers made by reacting a polyisocyanate, numerous examples ofwhich have been given hereinbefore, with a polyhydroxy compound of thekind with which this invention is concerned either as such or in theform of a polyester thereof having terminal hydroxy groups, alone oradmixed with a different polyester having terminal hydroxy groups, apolyhydric alcohol, a hydroxy-containing glyceride, etc. As prepolymersthere may be admixed with those just described, as desired or asconditions may require, prepolymers from, for example, tolylenediisocyanate and, for instance, castor oil, blown tung oil, blownlinseed oil or blown soya oil, prepolymers from tolylene diisocyanateand the polyester of ethylene glycol, propylene glycol and adipic acidhaving a molecular weight of, for instance, about 1900, and others suchas are described in the prior art, for instance, in US. Pat. No.3,133,978, column 6, lines 123, and in the patents referred to therein.

The halogenated, specifically brominated, monohydric or polyhydricethers of this invention may be employed alone in forming simple ormixed polyesters for use in the polyurethane compositions by reaction ofsuch hydroxy compounds with polycarboxylic acids such as malonic,adipic, succinic, sebacic, suberic, malic glutaric, maleic, fumaric,itaconic, aconitic, citraconic, phthalic, etc.; or they may be used inconjunction with other polyhydroxy compounds such as polyethyleneglycols (average molecular weights of, for example, from 400 to 3000),polypropylene glycols having, for instance, the same average molecularweights just mentioned, trimethylolpropane, ethylene glycol, diethyleneglycol, triethylene glycol, propylene glycol, dipropylene glycol,glycerol, 1,4-butanediol and others known in the art (see, for instance,US. Pat. No. 3,133,978, column 6, lines 24-47).

In preparing polyurethane foams a rigid foam is made, generallyspeaking, by utilizing a polyhydroxy-containing compound having ahydroxyl number of about 250-750; a semi-rigid foam, apolyhydroxy-containing compound having a hydroxyl number of about75-250; and a flexible foam, a polyhydroxy-containing compound having ahydroxyl number of about 25-75. The halogenated compounds of thisinvention are especially useful in the production of rigid polyurethanefoams and, somewhat less so, in making semi-rigid foams.

Any suitable blowing or foaming agent for the polyurethane resin may beemployed. Foaming may be effected by reaction of the isocyanate-modifiedpolyhydric compound with water; or, it may be effected by uniformlydistributing a liquefied halogen-substituted alkane containing at leastone fluorine atom in its molecule and having a boiling point at oneatmosphere not higher than 80 F., and preferably not lower than 60 F.,in the polyisocyanate reactant or in the polyhydroxy compound reactant.The reactants are then mixed, whereupon the reaction temperatureincreases during the resulting reaction to a temperature above theboiling point of the liquefied gas and a porous or cellular (i.e.,foamed) polyurethane is produced. Examples of fluorine-containingcompounds that are useful for this purpose includemonofluorotrichloromethane, chlorodifluoromethane,dichlorodifluoromethane, dichlorotetrafluoroethane anddichloromonofluoromethane. Information concerning the foaming ofpolyurethane resins with such fluorine-containing compounds is given in,for instance, British Pat. No. 821,342.

Until gas-producing agents such as fluorine-containing compounds becamein more common usage, the conventional method of liberating gascomprised the reaction of isocyanate groups in the organicpolyisocyanate component with carboxy-containing compounds or with waterpresent in the reaction mixture. By this technique CO is liberated insitu. Under appropriate conditions this gas then becomes entrapped inthe reaction mixture and, when the latter has become set or hardened,the resulting bubbles or cells are retained permanently in the resinousbody; that is, a foamed or cellular resinous structure has been formed.

EXAMPLE 7 This example illustrates the utilization of brominated polyolethers of the kind with which this invention is concerned as flameretardants in polyurethane foams.

(A) Preparation of prepolymers Control.A prepolymer for use in a controlpolyurethane foam formulation is prepared by reacting together 3523.5 g.of tolylene diisocyanate (more particularly a mixture of the 2,4- and2,6-isomers) and 780.3 g. of a conventional polyether of sorbitol, moreparticularly a conventional propylene oxide addition product ofsorbitol.

This prepolymer is prepared by charging the tolylene diisocyanate (TDI)to a reaction vessel and heating it therein to 65 C. under a nitrogenatmosphere. The sorbitol polyether is then added slowly with agitation,being careful to control any exothermic reaction. The reaction mixtureis heated with agitation to 90 C. and held at that temperature for 1hour. The resulting prepolymer contains 29.8% reactive (free) NCO groupsand has a viscosity of 4300 cps. at 30 C. The cooled prepolymer isbottled for subsequent use.

(1) Prepolymer of TDI and the brominated monoallyl ether ofanhydroenneaheptitol (DBMAE-AEH).

Formulation I G. DBMAE-AEH 103.8 TDI 396.2

The prepolymer is prepared by charging the tolylene diisocyanate (TDI)to a reaction vessel and heating therein to 70 C. under a nitrogenatmosphere. The brominated ether of the polyol (preheated if necessaryto keep it fluid) is then added slowly, watching for the exothermicreaction to begin and keeping the temperature below C. After all thebrominated compound has been added, the exothermic reaction is allowedto subside. The reaction mass is then heated to C. and held for 1 hourat that temperature after which it is cooled and bottled. The prepolymercontains 30.6% reactive NCO groups and has a viscosity of 2000 cps. at30 C.

(2) Prepolymer of TDI and the brominated diallyl ether of AEH(TBDAE-AEH).

Formulation G. TBDAE-AEH 133.3 TDI 366.7

The procedure is the same as in A-l of this example. The prepolymercontains 28.9% reactive NCO groups and has a viscosity of 302 cps. at 30C.

(3) Prepolymer of TDI and the brominated monoallyl ether ofpentaerythritol (DBMAE-PE).

Formulation G. DBMAE-PE 119 TDI 3 8 l The procedure is the same as inA-l of this example. The prepolymer contains 31.1% reactive NCO groupsand has a viscosity of 45 cps. at 30 C.

(4) Prepolymer of TDI and the brominated monoallyl The procedure is thesame as in A-l of this example. The prepolymer contains 30.3% reactive-NCO groups.

(5) Prepolymer of TDI and the brominated diallyl ether of sorbitol(TBDAE-Sorb.).

Formulation G. TBDAE-Sorb. 130.8 TDI 369.2

The procedure is the same as in A-l of this example. The prepolymercontains 30.6% reactive NCO groups.

(B) Preparation of foamed polyurethanes.-Control Formulation GramsPrepolymer of Control of A 150.0 Polyether of sorbitol 94.7

Silicone oil surfactant (siloxaneoxyalkylene copolymer), e.g., siliconeL-520 of Union Carbide 1.2 TMBA 1 (catalyst) 2.3 Freon-11 2 (belowingagent) 58.0

1 TMBA:N,N,N,Ntetramethyl-l,3-butanediamine. Freon-11 istrichlol'omonofluoromethane.

The reactants of the above formulation and of the formulations thatfollow are mixed and reacted together in accordance with conventionalpractice.

( 1) Formulation Prepolymer of A-l 125.1

Polyether of sorbitol 74.9 Silicone oil surfactant as in control 1.0Catalyst as in control 2.0 Blowing agent as in control 47.4

(2) Formulation Prepolymer of A-2 127.7

Polyether of sorbitol 72.3 Silicone oil surfactant as in control 1.0Catalyst as in control 2.0 Blowing agent as in control 47.4

(3) Formulation Prepolymer of A-3 124.3

Polyether of sorbitol 75.7

Silicone oil surfactant as in control 1.0

Catalyst as in control 2.0

Blowing agent as in control 47.4 (4) Formulation Prepolymer of A-4 125.6

Polyether of sorbitol 74.4 Silicone oil surfactant as in control 1.0Catalyst as in control 2.0 Blowing agent as in control 47.4

() Formulation Prepolymer of A-S 125.0

Polyether of sorbitol 75.0 Silicone oil surfactant as in control 1.0Catalyst as in control 2.0 Blowing agent as in control 47.4

Details of the mixing, rise and set times and of the results of tests onthe foamed polyurethanes are given in the following table. The test forflammability characteristics is conducted in accordance with theTentative Method of Test for Flammability of Plastic Foams and Sheeting,ASTM D-l692-59-T. The mix time (also sometimes designated as the creamtime) is the time from the beginning of mixing or agitation (e.g., at4500-5000 r.p.m. of the stirrer) to the beginning of frothing.

aryl and alkaryl radicals, x represents an integer from 1 to 2,inclusive, y represents an integer from 2 to 3, inclusive, 2 representsan integer from 0 to 1, inclusive, and x+y+z equals 4; and

(III) A blowing agent for polyurethane resins. Thus, the brominatedcompound of H may be, for example, mono(2,3-dibromopropyl) ether oftrimethylolpropane, mono(2,3-dibromopropyl) ether of pentaerythritol,and/ or bis(2,3-dibromopropyl) ether of pentaerythritol.

Or, (B) the flame-retardant, cellular, polyurethane resins are formedfrom mixtures comprising:

(I) At least one organic polyisocyanate;

(II) At least one brominated compound represented by the general formulawherein n represents a positive integer from 1 to 2, inclusive; and

(III) A blowing agent for polyurethane resins. Thus, the brominatedcompound of II may be, for instance, a mono(2,3-dibromopropyl) ether ora bis(2,3-dibromopropyl) ether of AEH.

Dr, (C) the flame-retardant, cellular, polyurethane resins are formedfrom mixtures comprising (a) at least one organic polyisocyanate; (b) atleast one brominated, ethylenically-unsaturated aliphatic hydrocarbonether of a sugar polyol; and (c) a blowing agent polyurethane resins.Thus, the brominated compound of (b) may be, for example, at least onedibromopropyl ether of sorbitol, e.g., monoand/or bis(dibromopropyl)ether of sorbitol, more particularly l-(2',3',-dibromopropyl) and/or1,6- (2',3'-dibromopropyl) ether of sorbitol.

TABLE-TEST CONDITIONS AND RESULTS IN PREPARING POLYURE- THANE FOAMS FROMBROMINAIED ETI-IERS OF POLYOLS Example No.

7-13-4 7-B-5 7-B-Control Mix time Rise time... Set time No. of specimenNo. of burns-.." Burning rate, in./min Density, lbs/cu. ft HumidityAged:

No. of specimens No. of burns Burning rate Compressive strength at 5%deflection Compressive strength at yield Percent Br 1 seconds. 2seconds. 3 20 seconds. 4 3 minutes. 5 3.5 minutes. 6 5 minutes. 1 16minutes.

wherein R, when present, represents a radical selected Catalysts andcatalyst systems that are suitable for accelerating the reaction betweenthe isocyanate and the halogen-, specifically bromine containingreactant include various tertiary-amine catalysts of whichN,N,N',N'-tetramethyl-1,3-butanediamine used in Example 7 is a specificexample; various organic tin catalysts, e.g., dibutyltin dilaurate; andcombinations of tertiary amines and organic tin compounds. Illustrativeexamples of other such catalysts that may be used as herein describedare given in, for instance, US. Pat. No. 3,159,591, col. 7, lines 36-57.

It is to be understood that the foregoing detailed description is givenmerely by way of illustration and not by way of limitation and that manyvariations may be made therein without departing from the spirit of theinfrom the group consisting of alkyl, aralkyl, hydroxyalkyl, vention.

wherein n represents a positive integer from 1 to 4, inclusive, and2,3-dibromopropyl ethers of sorbitol. 2. A flame-retardant, cellular,polyurethane resin which is formed from a mixture comprising:

(I) at least one organic polyisocyanate; (II) at least one brominatedcompound represented by the general formula wherein n represents apositive integer from 1 to 2, inclusive; and

(III) a blowing agent for polyurethane resins.

3. A flame-retardant, cellular, polyurethane resin as in claim 2 whereinthe brominated compound of II is mono- (2,3-dibromopropyl) ether ofanhydroenneaheptitol.

4. A flame-retardant, cellular, polyurethane resin as in claim 2 whereinthe brominated compound of II is bis- (2,3-dibrornopropyl) ether ofanhydroenneaheptitol.

5. A flame-retardant, cellular, polyurethane resin which is formed froma mixture comprising (a) an organic po1yisocyanate; (b)bis(2,3-dibromopropyl) ether of sorbitol; and (c) a blowing agent forpolyurethane resins.

References Cited UNITED STATES PATENTS 3,244,754 4/1966 Bruson et al.260-6l5 3,255,126 6/1966 Fuzesi et al. 2602.5 3,260,687 7/1966 Postol2602.5 3,318,960 6/1967 Earing 260615 3,385,900 5/1968 Carpenter et al.2606l5 3,419,532 12/1968 Jackson 260-77.5 3,252,922 5/1966 Degener etal. 2602.5

25 DONALD E. CZAJA, Primary Examiner M. I. WELSH, Assistant Examiner US.Cl. X.R. 260-775

